This is a study of the frequency and familial aggregation of malignant neoplasia in the Mexican-American city of Laredo, Texas. It is based on the automated linkage of hundreds of thousands of birth, marriage and death records into extended genealogies. Causes of death, by age and sex, will be mapped onto these genealogies, which will then be statistically assessed for evidence of risk heterogeneity for cancer which follows familial patterns. The study will include a complete historical-demographic and epidemiologic analysis of this city from its founding in 1785, as far as data allow. The purpose of this supplemental request is to permit the study to incorporate many more vital records into the study, bringing the total to over 400,000, doubling the number of deaths included, and raising the statistical significance of the results.